FIELD OF THE INVENTION
The present invention is related generally to illumination systems and more particularly to illumination systems utilizing polarized light.
The benefits of using polarized light for illumination in offices, stores, manufacturing facilities, and the like have been recognized. See, for example, Lumsden, Effective Task Lighting Using Polarized Light, LIGHT AND LIGHTING, July/August, 1976; and Comparison Report on Polarized Panels v. Conventional Prismatic Lenses, published by the Polarized Corporation of America of 8921 Quartz Avenue, Northridge, Calif.
The polarized light used for interior lighting reacts differently in response to the orientation of the illuminated surface. For example, vertically plane-polarized light tends to be absorbed and re-emitted from horizontal surfaces but reflected from vertical surfaces in the form of a light-veil commonly referred to as glare. In an office or manufacturing setting, it may be possible to minimize the number of vertical surfaces such that the amount of overall glare is substantially reduced. However, in a surgical setting, even assuming that the number of vertical surfaces may be reduced, some small number of vertical surfaces will still be present which will result in the production of glare which may periodically obscure the surgeon's vision. Such a situation is totally unacceptable in a surgical setting.
It has been suggested to eliminate the amount of glare produced by various surfaces or wet tissue in a surgical incision by inserting a polarized filter between the surgeon and the patient. This second polarized filter would function much the same as sunglasses do in eliminating glare. Unfortunately, polarizing filters typically have transmission factors which may vary from 22% to 55%. Thus, positioning a polarizing filter in front of the light source and positioning a complimentary polarizing filter between the surgeon and the patient drastically reduces the amount of light which reaches the surgeon's eyes. Any visual enhancement gained by the polarization is lost due to the insufficient illumination.
Attempts to overcome these optical losses by pumping more energy into the light source have proved unsuccessful. The heat generated by the increased power has proved unacceptable in a surgical setting. Additionally, the costs involved in providing a light source capable of handling such high power have proved prohibitive. Thus, polarized light has not heretofore been used in surgical settings or other settings involving these types of problems.